Polypectomy snare instruments are used for the endoscopic removal of hypertrophic tissue growths within a body cavity, and particularly within the colon. Polypectomy snare instruments generally include an elongate tubular member, such as a catheter sheath, a shaft extending through the tubular member, a wire forming a snare (loop) at the distal end of the shaft, and a handle for moving the shaft distally and proximally within the tubular member. The snare can be opened by moving the snare beyond the distal end of the sheath and closed by retraction of the snare into the tubular member, each effected by movement of the shaft relative to the sheath. A number of different types of snare devices exist, each having certain advantages and disadvantages. There is an ongoing need for refined snare devices.